Handler fails with error "Cannot read property 'forEach' of undefined" about retinal HOT 2 CLOSED

{
  "name": "serverless-sharp-image",
  "provider": {
    "profile": "serverless-admin",
    "stage": "dev",
    "region": "eu-central-1"
  },
  "sourceBucket": "foo-bucket",
  "sourcePrefix": "uploads",
  "destinationBucket": "foo-bucket",
  "destinationPrefix": "images/resized/",
  "s3": {
    "params": {
      "Metadata": {
        "generator": "created by a serverless-sharp-image lambda function"
      }
    }
  },
  "all": [
    ["rotate"],
    ["toFormat", "jpeg", { "quality": 80 }]
  ],
  "outputs": [
    {
      "key": "%(filename)s-200x200.jpg",
      "params": {
        "ACL": "public-read"
      },
      "operations": [
        ["resize", 200, 200],
        ["max"],
        ["withoutEnlargement"]
      ]
    },{
      "key": "%(filename)s.jpg",
      "params": {
        "ACL": "public-read"
      }
    },
    {
      "key": "%(filename)s-100x100.jpg",
      "operations": [
        ["resize", 100, 100],
        ["max"],
        ["withoutEnlargement"]
      ]
    }
  ]
}